Abstract: Wall thickness precision control is crucial to quality control of large-diameter high-pressure gas cylinders. This paper integrates modern statistical methods, takes several key parameters such as mean value of average wall thickness, standard difference and standard difference coefficient as evaluation standards for wall thickness precision large-diameter high-pressure gas cylinders, fulfills full-length manual measurement of such the gas cylinders, and analyzes gas cylinder wall thickness precision transfer property by combining UT flaw detection. Statistically, the overall wall thickness of gas cylinder displays a normal distribution. In this paper, an analytical model for ability control of gas cylinder wall thickness precision is proposed, so that the evaluation on wall thickness precision and process ability is made possible for mother tube, semi-product tube and product tube in the trial production of gas cylinder tubes, and accordingly technical supports are supplied in practical production.